The computer-animated comedy ”Ice Age” was expected to storm the multiplexes this weekend, but no one dreamed it would snowball to an estimated $47.9 million opening. The movie managed to freeze out the competition while heating up the overall box office for the weekend to a level usually not seen until summer.

Even Twentieth Century Fox’s most optimistic projection for ”Ice Age” was about $30 million. But teens and young adults apparently found the film hip enough to augment its family audience and boosted it to a record March opening, well ahead of 1997’s Jim Carrey comedy ”Liar, Liar” ($31.4 million). ”Ice Age” also saw the third-best opening ever for an animated feature – after ”Monsters, Inc.” ($62.6 million) and ”Toy Story 2” ($57.4 million) – and finally made Fox an animation player after such expensive hand-drawn fizzles as ”Anastasia” and ”Titan A.E.”

Coming in a distant second was ”Resident Evil,” whose estimated $18.2 million opening was nonetheless very strong for a film without A-list stars that originated as a videogame. As Sony Pictures tracking indicated, the appeal of zombie-battling babes Milla Jovovich and Michelle Rodriguez extended to teenage girls as well as teenage boys. In contrast, only 40 percent of the audience for the Warner Bros. Eddie Murphy-Robert De Niro buddy-cop spoof ”Showtime” was under 25, and the movie opened at No. 3 and collared an estimated $15.4 million.

Dropping drastically in their second week were ”The Time Machine,” which lost 52 percent of its audience to come in fourth at $10.9 million, and ”All About the Benjamins,” which fell three places to No. 6 with a $4.9 million take. (At No. 5 was veteran ”We Were Soldiers,” with $8.8 million). Still, the top 12 movies grossed $124.2 million, a level Hollywood usually has to wait until summer blockbuster season to reach. Expect the box office thermometer to drop back down to a seasonal chill next weekend, when the competitors will include ”Blade 2,” ”Sorority Boys,” and the rerelease of ”E.T. the Extraterrestrial.”